1. Field of the Invention
This invention relates to keyed connectors and more particularly to keyed connectors having dimensions similar to but which cannot be mated with standard connectors.
2. Description of the Prior Art
Long marketed connector systems commonly known as MICRO-RIBBON connectors (a trademark of Bunker Ramo Corp.) are useful for interconnecting two cables, each having a plurality of wires therein. Such connectors, when embodied as either a plug or a receptacle, have an outer shell which retains an inner contact mounting insert. For a plug, the contact mounting insert has a central, upwardly extending tongue formed of parallel contact-retaining walls and end walls spaced a standard length by the retaining walls. A typical receptacle has a contact mounting insert with an aperture therein formed by parallel contact-retaining walls and end walls spaced a standard length by the retaining walls. The contacts on the contact supporting walls of the plug and receptacle align and mate when the units are plugged together.
In many applications, some of the connectors have low voltages associated therewith and others have high voltages. It is undesirable to permit a situation to exist in which a low voltage connector can be accidentally joined to a non-compatible high voltage connector. In particular, it is advantageous to prevent the mis-mating of data system connectors with telephone system connectors. In such cases, voltage level differences of up to 110 volts can occur. Also, even if the connectors do no exactly mate, the possibility that a conductive contact adjacent an end portion of one of the connectors might be tipped into contact or at least near to some of the contacts of the other connector poses a problem. Also, the contacts of non-compatible connectors may approach each other if an attempted head-on insertion is made. A high voltage arc may then occur when the high and low voltage contacts come sufficiently close together to permit an arc between them. Also, government requirements exist requiring connectors carrying high voltages to be polarized so that they can intermate only with similarly polarized mating halves and thus cannot short out any low voltage non-polarized connectors.
Examples of prior art patents which illustrate the use of keyed plugs and receptacles are Desso et al (U.S. Pat. No. 3,651,444), McDonald (U.S. Pat. No. 3,656,090), Gallagher (U.S. Pat. No. 3,930,705), Bertram et al (U.S. Pat. No. 3,002,175), Wilson (U.S. Pat. No. 3,953,099) and Yopp (U.S. Pat. No. 3,002,176). These patents are not pertinent to this invention since they do not teach the use of the connector system which uses a standard connector dimension but has a contact mounting insert with a contact supporting means which utilizes the keying means of this invention.